Shuttle-type air guns known prior to the present invention generally include as their operating components a firing chamber for holding a charge of gas under high pressure, usually compressed air, a two-piston shuttle which can be triggered to abruptly release this charge of pressurized gas through discharge ports, means for supplying gas under high pressure to charge the firing chamber, and a solenoid-operated valve for causing the shuttle to be actuated for suddenly discharging the pressurized gas from the firing chamber. The two-piston shuttle has a firing piston positioned near the firing chamber for retaining the charge of pressurized gas therein and an operating piston positioned in an operating chamber wherein pressurized gas acts against this operating piston to maintain the shuttle in a closed position until it is released. The pistons of the shuttle are interconnected by a shaft or shank which is hollow for permitting a supply of pressurized gas to flow from the operating chamber through the hollow shank into the firing chamber for charging the latter chamber.
There is copending a patent application entitled: "METHOD AND APPARATUS FOR CONVERTING AN AIR GUN INTO A HYDRO GUN FOR MARINE SEISMIC IMPULSE GENERATION", U.S. Ser. No. 680,733, filed Dec. 12, 1984, in my name as sole inventor. The reader is referred to the specification, drawings and claims of that patent application as background information for better understanding the present invention. This present invention provides improvements and advantages over the air gun and hydro gun apparatus disclosed therein.
There is also a copending patent application entitled: "AIRGUN HAVING SHAFT-BEARING-GUIDED SHUTTLE AND CAPABLE OF FAST REPETITION SELF-FIRING", U.S. Ser. No. 672,107, filed Nov. 15, 1984, in my name as sole inventor. This latter patent application describes an air gun and does not describe a hydro gun.
The present invention, in certain of its aspects, provides improvements and advantages over the apparatus disclosed in the latter application.